Switches comprise backside ports and frontside ports. Backside ports are used to, for example, connect one switch to another switch to form a switch stack, or a stacked switch. Backside ports typically have a maximum link distance of five meters or less, but communicate at a very high speed. Frontside ports are ports used to typically attach devices to the switch. The advantage of frontside Ethernet ports is that they can connect devices over long distances, but at a speed slower than the connection speeds of backside ports.
In the past, switches that were spaced far apart could be connected together in a ring using two of the frontside ports. As only two frontside ports were available for frontside stacking, ring topologies have been the only topologies available, making mesh and other interesting configurations impossible. In addition, prior switches could not support hierarchical etherchannel communications, such as that which may be implemented in “ring of rings” topologies. Furthermore, in hierarchical topologies that implement multiple levels of stacks between access nodes and a core node, there have not been methods to efficiently load balance the traffic or avoid traffic flowing over unnecessary links. In addition, prior systems failed to perform déjà vu checks based on global port numbers and intermediate port numbers.